1. Field of the Invention
This invention relates to filled and plasticized blends of ethylene interpolymers and more specifically it relates to such blends modified with organic acids.
2. Description of the Prior Art
Japanese Patent Publication 23128-1980 describes filled ethylene copolymer compositions (in particular, ethylene/ethyl acrylate; 5 to 30% ethyl acrylate) with 100 to 500 parts by weight of a inorganic filler which has been surface-treated with a titanate-based coupling agent (e.g. isopropyl triisostearyl titanate). The compositions which result are claimed to provide noticeably improved tensile strength, elongation at break, strechability, and heat shrinkage, vs. compositions which do not employ titanate-based coupling agents.
Japanese Patent Publication 21052-1980 describes a filled polymer composition which uses as raw materials a polymer mixture of (a) ethylene/vinyl acetate (EVA) copolymer, which contains from 10 to 28% vinyl acetate; (b) rubber, preferably chloroprene rubber or ethylene-propylene rubber, and (c) filler. The ratio of EVA:rubber is from 60:40 to 90:10. The mixture should contain 100 parts of polymer mixture and 150 parts of a high specific gravity filler. It may optionally contain other ingredients, such as dibutyl phthalate as a plasticizer, and stearic acid. It is intended for use in vacuum-molded sheet or in injection molded form for sound-deadening purposes.
U.K. patent application No. 2,067,576A describes a composition which contains three essential ingredients--10 to 25% of a thermoplastic resin component (such as ethylene/ethyl acrylate or ethylene/vinyl acetate copolymers), 4 to 15% of an olefinic elastomer (such as ethylene/propylene rubber; ethylene/propylene/diene rubber, or polyisobutylene/isoprene copolymer), and from 60 to 85% of a filler component, such as barium sulfate or calcium carbonate. Optional additional ingredients include 0.25 to 2.0% of stearic acid and stearates which allegedly function as a processing aid; 2 to 10% of a paraffinic or naphthenic hydrocarbon oil; tackifying resins; titanates or polymeric ester surface-treating aids, etc. Carpet constructions employing the above compositions are also disclosed. The compositions described in this application are alleged to offer unusually high flexibility as compared with blends known heretofore.